Combination filament crusher and circuit breaker for safety hand lamps



Oct. 7, 1952 E J. GARLAND 2,613,314

COMBINATION FJELAMEINT CRUSHER AND CIRCUIT BREAKER FOR SAFETY HAND LAMPS Filed Nov. 5, 1947 2 SHEETS-Sl'iEET l JNVENTOR. fem/am J ar/am ZJ W F77 7 ORA/1f V Oct. 7, 1952 E. J. GARLAND 2,613,314

I COMBINATION FILAMENT CRUSHER AND CIRCUIT BREAKER FOR SAFETY HAND LAMPS Filed Nov. 3, 1947 2 SHEETS-SHEET 2 I I I 723 32 7% 74 Z6 Z6 5/ 2/ 3 3g 5 H 30 7 'l' 52 5 4 a? INVENTOR. v

. a Edwarc/Jar/awd Patented Oct. 7, 1952 COMBINATION FILAMENT c UsnnR AND CIRCUIT BREAKER FoR SAFETY HAND LAMPS Edward J. Garland, Worcester, Mass, assignor to Blake Manufacturing Corporation,

Ciinton,

pl Mass, a corporation of Massachusetts I r Application November 3, 1947, Serial No. 783,695

;, I 4 Claims.

This invention relates to flashlights utilizing prefocused bulbs andmore. particularly to socalled safety or explosion-proof hand lamps. Flashlights or'portablehand lamps energized by a battery are prohibited bylaw from being used in areas exposed'to explosive mixtures of gases Or vapors with air, suchas are met with in so called gassy mines" and around pi] refineries, distilleries, and installations handling combustible, vaporizable liquids,"un1ess they are provided with automatic means, operable upon breaking of the bulb, to simultaneously crush the filamentof the bulb and break the electric circuit between the bulb and the battery. i

Various devices .I have been proposed and put inuse for effecting the conjoint crushing of the filament and breaking of the circuit upon breakage of the bulb The mechanisms used are, in the main, complex 'andbulky and require a multiplicity of par-ts. With'prefocused bulbs, positive seating of the lamp base is required, and this has been attained by providing separate sleeve members'having bearing engagement ina cap and against the flange of the lamp base'when the cap is adjusted to force the retaining sleeve into lamp-supporting position; Additionally, the mounting of a contact bar in normal closed circuit relation with th base of a lamp involves the incorporation of separate" switch mechanisms with the lamp support and its mounting cap. The mounting" of aspring-biasedsbreaker bar in engagement with the-bulb of the lamp and se cured to an actuator, operable to unseat the contact disc 'upon the spring-biased plunging movement of thebreaker bar to crush the filament, introducefurthercomphcated mechanisms ,v

into a situation'where space is ata premium.

It has now been found that a combination filament crushe'r and circuit breaker canbe incorporated in an oilicially approved so-called mine safety lamp." I Essentially, in a flashlight embodying the present invention, a reflector is equipped witha-short tubular extension into which is fitted a lamp receptacle comprising a metal tube having a neckedin endportion with an inturned flange forming a shoulder and being internally threaded at its other end. The necked-in portion of the receptacle is fitted into the tubular extension of the reflector and secured therein in any suitable manner well known to "those skilled in theart. The

lamp receptacle receives a lamp hold=down piece or screw shell, 'made of suitable insulating material, and screw-threaded, to a depth sufficient to insure the positive bearing engagement of the Hit-41.3)

2 end of the tube against the flange in the lamp receptacle. The plastic shell has a uniform inner diameter and is of a depth sufficient to receive the lamp base of a prefocused lamp, together with a lamp-contact spring which is secured to a suitable contact extending through the bottom Wall of the shell. Such a contact may be a hollow rivet or eyelet. The outer surface of the plastic shell between the end and the outer screw threaded portion is desirably formed with a conical configuration to receive the knurled open end of a contact cup, which is fitted thereon and interlocked therewith. The conical section is required to provide a suilicient bearing surface to insure positive and permanent retention of the contact'cup in position, so as to form a structural entity with the plastic shell. The

contact cup is provided with a pair of opposed apertures which receive the arms of a brass contact disc which is normally urged into contact with the connector or contact in the base of the sleeve byacompression spring seated in the bottom of the contact cup and having flat bearing engagement against the opposed bottom face of the: contact disc. The base of the contact cup will have normal bearing engagement withthe center terminal of the battery.

. With the composite plastic lamp hold-down and contact cup as a structural entity, the normal mounting of the prefocused lamp in the lamp receptacle is not only greatly simplified but posi tively assured by the bearing engagement of the end of the-hold-do'wn against the flange of the lamp base, clamping the latter in fixed position against the conductive shoulder of the lamp receptacle. There is no multiplicity of parts to be assembled and dismounted and the unitary hold-down being of insulating material subserves the added useful function of combined lampcasing and circuit breaker mounting.

The simplicity of the device herein will be readily appreciated in considering its incorporation' into a mine safety lamp structure. The base of the reflector is provided with apair of diametrically opposed vertical slots which receive the legs of a hard Wire breaker bar on which is mounted a crushing member, desirably of cup shape, whose function is to engage and crushth'e lamp filament. The ends of the legs are bent into everted hook form and these hooks are received in opposed slots in an insulating bushing or ring. A compression spring has bearing engagement against'the rear-wall of the reiiector and the upper surface of th insulating ring or actuator; I i

With the lamp base set in the plastic holddown, the latter is inserted into the lamp receptacle and screwed up therein with the tip of the lamp in bearing engagement with the cup mounted on thebreaker bar. As .the hold-down forces the lamp up into its receptacle, the'breaker bar is forced upwardly carrying the actuator or bushing upwardly against the bias of the compression spring. When the hold-down is inserted to its full length, the flange of the lamp base will be secured between the hold-down and the shoulder of the lamp receptacle and the lower edge of the bushing or actuator will override and be spaced from the extending arms of the :contact disc of the circuit breaker. The compression spring biasing the breaker bar and actuator must be stronger than the spring to bias the contact disc into engagement with the contact in the base of the hold-down sleeve. When the bulb breaks, thecom-pression spring biasing the breaker bar and the actuator will move both members simultaneously to crush the filament of the bulb and engage the lugs of the contact disc and unseat the latter, thereby breaking the electric circuit to the lamp.

The above and other desirable objects and features of novelty and advantage of the :pres ent invention will become apparent from the specification and accompanying drawings, wherein:

Fig. 1 is a longitudinal section through .a flashlight with the batteries and the reflector and switch housing being shown in elevation;

Fig. 2 is a horizontal section taken on line 2-2 of Fig. 1, showing the apposition of the 'breaker'bar and lamp bulb;

Fig. 3 is a horizontal section taken on line 3.-13 .of Fig. 1, showing the. lamp mounting and switch mechanism;

Fig. 4 is a horizontal section taken on line 4--.4- of Fig. 1, showing the mounting of the contactor .clisc;

Fig. 5 is a detail vertical section through the reflector and lamp housing, showing the bulb and breaker bar in normal position; and.

Fig. 6 is a view similar to Fig. 5 showing the bulb and filament crushed by the circuit breaker bar and the contactor disc unseated.

The flashlight shown comprises a tube ill of insulating material, with an inner lining 12 comprising a metal tube such as brass, the inner metal tube being flared slightly at one end. as indicated at H, and provided with a terminal threaded portion l3. A metal hood [5 has a necked-in bottom portion in threaded engagement with the upper end 13 of the casing, as indicated at [6. The upper end of the hood I5 is threaded, as shown at H, and is engaged by the threaded skirt 18 of lens ring 19. An insulating hood 9 is mounted on and over the hood l5 and the subjacent portion of casing 10. The end cap I8 has an inner metallic cup liner [9 threaded to engage the screw threads [4 of the conductive liner of the casing, The hood and the end cap are sealed, as shown. to prevent unauthorized tampering with the flashlight. A compression spring 2 is seated in the metallic cup l9, and has bearing engagement against the bottom of cell 3, which, together with upper cell l comprises the battery of theflashlight, as shown.

he r l ctor 20 comprises a parabolicbowl having a tubular extension 2!. at the base and a flange 22 at the periphery of the reflector bowl. A channeled insulating ring or annular strip 23 is secured over flange 22. Lens 24, desirably of plastic, is clamped against the reflector by the lens ring is and the extended skirted portion of the insulating ring 23 has bearing engagement ragainstthe upper end .ofmetal hood [5, the latter clamping Ihe reflector firmly in place.

A switch member 5 has a slidable leaf spring 6 with an angular tip 8 which is movable into circuit making contact with the reflector. The bowl of the te'flector is provided with diametrically opposed :slots 26 adjacent the tubular extension Zl. These apertures serve to receive the ,endsof the breaker bar, as will be described more in detail hereinafter.

"The flashlight hereln is of the so-called prefocused lamptype and the special mounting of the lamp will now be described. The lamp receptacle 30 comprises an open ended tube having an upper wall section 31, inturned, as shown at 232,110 provideaseat for theflange of a prefocused typelamp base. The tubular section 3| of member 30 is fixedly secured in extension 2| of the reflector, in any suitable manner. Below the tubular section .31, the lamp receptacle is flared outwardly, as shown at .33., and then continued downwardly to :give a central section of substantially uniform diameter. The bottom of the tubular lamp housing is internally threaded, as indicatedat 35. Aplastic screw plug or shell 40 comprises a cylindrical body section 4| and a centrally .apertured base 42. The plastic shell 40 has an inner chamber of substantially uniform diameter and designated generally by numeral 43. The top section 44 of wall 41 is loosely fitted in section 31 of the lamp receptacle, and its upper portion has normal hearing engagement with the shoulder 32 of the lamp receptacle, when the plug is screwedup into the receptacle. The wall 4| flares outwardly below the section 44 and terminates man externally. screw threaded section 45 adapted for threaded engagement with section 35 of. the lamp receptacle. The bottom section 42 cf the plug is beveled to provide a frustoconical surface, as shown at 46, to provide a bearing surface for the rim 62 of the conductive cup of an automatic circuit breaker. A contact spring 41 is mounted in the cavity 42, and is fixedly secured in its base to a conductive disc or washer 8 which isheld in position by the upper head of arivet or stud 49, the'lower head of which provides a base terminal contact.

The lamp 50 comprises a bulb 5| mounted in a ferrule 52 having a shouldered flange 53 and a base terminal 54. The ferrule or lamp base is inserted'into the cavity 43 of the insulating plug which is then screwed up into the lamp receptacle until the flange 53 is forced into conductive bearing engagement" with the'shoulder 32 of the receptacle. The base terminal 54 of the lamp will be in conductive connection with terminal 49 through spring 41 and disc 48. With this construction, it will-be seen that the lamp is positively; clamped inposition, and because of the mounting'of the shoulder 32 of the lamp receptacle; the. filament in'the lamp is accurately positioned at the focus of the reflector. By shiftmg thepositionof shoulder 32 in the tubular extension 2| ofzthe. reflector, any predetermined focal length can be attained.

One leg-of theelcctrical circuit of the lamp filament will. be seen to comprise the compression springx2 at the base of theflashlight, the inner conductive wall [2 of the flashlight, the switch blade or leaf 6, reflector 20, lamp receptacle 30, flange 53 and ferrule 52 of the lamp base.

The other side of the circuit comprises a base terminal 54 of the lamp, the spring connector 41, connector 48, and stud 49 connected through circuit breaker 66 to the center electrodeof the upper cell of the battery. The special circuit breaker 60 will be seen to comprise a conductive cup shaped member having side wall 6|, the upper edge 62 of which ispeened or rolled over in looking engagement with the conical bearing surface 46 of the insulating plug. A pair of arcuate spacers 63 are secured in the periphery of the base of the insulating cup, as by molding, and bear against the base of the conductive cup. These spacers may be formed as part of a cylindrical member with diametrical cut-outs to receive the lugs of the contactor disc. The base 64 is provided with a raised annulus 65 defining a central socket to receive the apposed electrode of the battery, and to serve on the interior of the conductive cup 60 as a seat for compression spring 66. The wall 6| of the circuit breaker casing is bilaterally apertured, as indicated generally at 61, to receive extended lugs 68 of contactor disc 69. It will be noted that the bearing surfaces of spring 66 are parallel. With the contactor disc of the contactor housing and the stud 49 of the plastic screw shell through spring 66 and disc 69.

The special lamp mounting and in-tegral' circult breaker, described immediately above, provides a unitary construction which'is especially adapted for use in mine safety flashlights wherein it is desired'th'at the electrical circuit to the lamp filament be broken simultaneously with the crushing of the lamp filament upon breakingof the lamp bulb. This desirable result is attained in the followingmanner:

A breaker bar or crusher comprises a cross member H, here shown as mounting a cup member 12, brazed or otherwise secured to the bar, as indicated at 13. The bar H is provided with depending legs l4 passing through slots 26' in,

the reflector, and terminating in everted hooks 75 which are received in opposed slots 16 of an insulating annular bushing or actuator 11. A compression spring 78 is disposed'between and bears against the under surface of reflector and the top end of actuator 11] It will be understood that the wall thickness of actuator 11 should be great enough to provide adequate bearing surface for the lower end of spring 18 and adequate bearing surface to engage lugs 68 of contact disc 69, at the opposite ends of actuator l! respectively. The length of actuator 11 is so proportioned that its lower end is out of bearing engagement with lugs 68, while spring 18 is held under compression, where crusher I2 is supported on an unfractured bulb. Note Figure 5. In this position contact disc 69, spring 66, circuit breaker 66 and stud 49 are in conductive contact to complete the circuit between the base terminal of the lamp and the central terminal of cell 4. When the lamp bulb is fractured for any reason, spring 18 is free to expandthus simultaneously crushing the lamp filament and depressing actuator 11. The depression of actuator 11 brings its bottom end into engagement with lugs 68 and through these lugs depresses contact disc 69 against the resistance of weaker spring 66. The depression of contact disc 69 breaks the circuit between cell 4 and the base terminal of the lamp bulb by moving contact disc 66 out of contact 6 with stud 49. The elements ll, 14 and of crusher "I0 are made of hard wire such as steel.

It will now be appreciated that there has been provided a novel mine safety flashlight incorporating a special combination prefocused type lamp holder and circuit breaker as a structural entity and which can be readily assembled and disassembled.

It is, of course, understood that various modifications may be made in the structure above described without many way departing from the spirit of the: invention as defined in the appended claims.

What is claimed is: 1

l. A portable safety hand lamp comprising a reflector having a tubular extension at its base, a conductive lamp receptacle adapted at-its upper end for fixed positioning within said tubular extension, an insulating plug, threadedly connected with said lamp receptacle, said plug having a cylindrical interior boreadapted to receive the base of a .pre-focused lamp, a conducting bulbsustaining spring within said bore, said spring, said plug and said lamp receptacle cooperating to support said lamp in fixed position, a conductive element extending through the base of said plug and in conductive contact with said conducting spring, a conducting cup affixed to' thebase of said plug, said cup having a base adapted for direct contact with a battery terminal, slots within the walls of said cup, 'acontact plate disposed within said cup said contaotplate having a plurality of ears which extend laterally through said slots and beyond the side wall or said cup,

a second spring Within said cup, said second spring being in conductive contact with said cup and said contact plate and yieldingly urging the latter into engagement with said conductive ele ment in said plug basepan insulating tube surrounding said lamp receptacle, a lamp filament crushing member having depending arms which engage said insulating tube, said tube having appreciable wall thickness'and having an inner diameter appreciably greater than the maximum exterior diameter ofsaid' lamp receptacle, the inner diameter of said tube being smaller than the maximum distancebetween the ends of said ears, a third spring mounted between said reflector and said insulating tube, said third spring being adapted upon breaking of the lamp bulb to depress said insulating tube to engage said ears and depress said contact plate out of engagement with said conducting element in said plug base.

2. A portable hand lamp comprising a reflector having a central opening and a depending tubular extension surrounding said opening, an internally threaded boss provided with an unthreaded upper neck portion adapted for seating within said tubular extension and having an inturned flange on the upper end thereof,a flanged prefocused lamp mounted in said boss and having a bulb and a base terminal, said flange on the upper end of said boss being of lesser diameter than the flange on said lamp, thereby pro viding a seat for said lamp flange, an externally threaded insulating sleeve th'readedly mounted within saidth'readed boss and adapted to embrace the base of "the lamp, the upper end of said sleeve being of approximately the same diameter as said flange on the lamp whereby said flange on the lamp is clamped between said inturned flange on the top of said boss and the upper end of said insulating sleeve, contactor means in the base of the insulating sleeve, said contactor means providingv resilient engagement with'the base terminal of the lamp and extending through the bottom of thesleeve, a circuit breaking contact disc mounted exteriorly of, the base of said sleeve, disc mounting means connected with said insulating sleeve for mounting-said disc exteriorly of the base of said insulating sleeve, spring means disposed between said disc and said disc mounting means normally biasing said disc into engagement, with the contactor means in the base of the sleeve, a lamp filament crushing member arranged within the-reflector over the lamp bulb, said lamp filament crushing member having depending arms extending through the reflector, a cylindrical insulating tube disposed coaxial with, but spaced from, said threaded boss and said insulating sleeve inserted in said boss and having a top end and a bottom end, the inner diameter of the bottom end of said insulating tube being smaller than the diameter of said contact disc, said depending arms on the lamp filament crushing member being connected to said cylindrical insulating tube adjacent the top end thereof, and a biasing spring disposed between the lower surface of said reflector and said top end of the insulating tube, whereby upon breakage of the lamp bulb said lamp filament crushingmember and said insulating tube are moved downward by said biasing spring, said bottom end of the insulating 0 tube strikes and moves downward said contact disc out of contact with said contactor means in the base of said sleeve.

3. A portable safety hand lamp comprising a reflector having a central opening, a tubular extension below said opening, and a plurality of slots in the reflector wall, a lamp support mounted within said tubular extension and in spaced relation thereto, said lamp support comprising an exteriorly threaded cylindrical insulating plug, a metallic sleeve having an inturned flange at its upper end and attached at its upper end to said tubular extension on said reflector, said sleeve surrounding the major portion of said insulating plug and being internally threaded to receive said insulating plug, said flanged end of said sleeve and the upper end of said plug providing a seat therebetween adapted to position a prefocused lamp in predetermined fixed position with respect to said-reflector, a flanged prehaving its flange seated between the end of said insulating plug and said inturned flange on the metallic sleeve, said lamp having a bulb and a base terminal, a yieldable contact mounted within said plug and engaging the base terminal of said lamp, a contact member conductively connected to said yieldable contact and extending through the base of said plug, an insulating tube positioned coaxial with but spaced about said insulating plug, a filament crushing member arranged within the reflector over the lamp bulb, the ends of said member extending through said slots in the reflector and being connected with said insulating tube and thereby supporting said insulating tube, a spring mounted between said insulating tube and said reflector, a cup member fixedly mounted on said base of the insulating plug, a spring mounted on the-interior base of said cup member, a circuit breaking contact plate mounted above saidspring, within said cup membe and being provided with ears which extendexteriorly of the wall; of said cup member and beyond the confines of the bottom end of the inner; wall of said insulating. tube,-said circuit breaking contactplate being normally spring biased into conductive contact with the contact member in the base of said plug but being adapted to be pressed out of engagement therewith by, said'insulatingtube upon the breakage of the bulb ofthe lamp.

- 4. In a portable safety hand lamp comprising a reflector, a prefocused lamp bulb mounted within said reflector, a' lamp filament crushing member supported by said lamp bulb and having armswhich depend belowsaid reflector, the improvement which comprises-in combination fixed lampisupporting means, circuit breaking means, and means distinct from said lamp supporting means for actuating said circuit breakingmeans uponthe-breakage of the lamp bulb, said lamp supporting means comprising an insulating plug member exteriorly threaded and having an interior recess to accommodate the lamp base, a plug contact member extending through the base of said plug and a spring mounted within said recess and in contact with said plug contact member'for providing a resilient conductive connection between said lamp base and said plug contact member, a metal sleeve having an inturned transverse flange at its upper end mounted. on said reflector and being threaded atits lower end for engagement by said insulating plug-member thereby providing a fixed support for the flange of the prefocused bulb between said flange on the metal sleeve and the upper end of said plug, said circuit breaking means comprising,a conductive cup mounted onthe base of said insulating plug and depending therebeneath, a spring'mounted on the interior base of said cup, a contact plate mounted above the spring in said cup and having ears extending exteriorly of said cup, said contact plate being adapted to engage said plug contact member below the base of said plugin closed circuit position, a spring biased insulating collar, coaxial with said lamp supporting means but spaced apart therefrom, said insulating collar being normally supported by said lamp filament crushing member mountedon the bulb of the lamp and being out of engagement with the ears of said contact'plate but being adapted to engage said ears and depress said contact plate thereby breaking the connection between said contactplate and said plug contact member upon the breaking of the lamp bulb.

' EDWARD J. GARLAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

